Solar cell, also known as photovoltaic cell, technology is increasingly useful as energy costs and people seek environmentally friendly “green” ways to generate power. However, current solar cells are opaque, limiting their use in commercial and residential building to rooftop installation with no functionality other than creating energy. This precludes their use in a variety of applications that require transparency. In particular if solar cells were transparent they would be useful as windows. Since glass windows are a common feature to many building, both commercial and residue, windows that can be made both to generate energy and to allow illumination into the building are beneficial. Windows are extremely common and are found on all types of building; homes, apartments, office, and other institutions; both vertically installed and horizontally, such in skylights. Additionally, dual uses as a polarized and solar window would be useful for shading, darkening, and for energy generation.
Until this invention, no other patent has disclosed the ability to provide solar power with a transparent and viewing window for energy generation.
The usefulness of using windows for solar cell has been a goal for many researchers. Solar windows have been disclosed that integrate solar cells in the window itself, in a decorative pattern or as a replacement for glass panels. U.S. Pat. No. 4,137,098 discloses an array of solar cells in a Venetian blind configuration which can be opened or closed to let in light. U.S. Pat. No. 5,128,181 discloses a combination of solar cell and solar heating panel integrated together. U.S. Pat. No. 6,646,196 discloses a simple arrangement of window panes and a solar cell panel installed in a frame that can be placed in a window opening, the same panel that can be installed on roof-tops. All these inventions integrated silicon wafer solar cell technology arranged to create windows, but the solar cell is not the window itself. Limitations arise as to the amount of light that can be allowed into the room where the window is.
U.S. Pat. No. 6,688,053 shows a double paned, solar power window that encloses solar cells and dichromatic mirrors between the two panes, thus using the reflected light to generate electricity. This patent combines three functions into one, relying on integration of these components. The light directed to the solar cells relies on dichromatic mirrors to direct all wavelengths of light to mirror. The cells are arranged in a manner to allow light into the building while also generating electricity. A converter is required to transform DC to AC. The physical dimensions are not disclosed, but the thickness of the window is assumed to be of the order of an inch and may be limited for residential applications. Also, the integration is quite costly and required three separate components. Also of limitation is the light allowed into the room.
U.S. Pat. No. 7,019,207 discloses a thin film solar panel that could be used for window applications, the etched transparent lines act as Venetian blinds allowing light to enter a room, providing partical shade. However, the blinds cannot be modulated, they are permanent fixtures. Because patterns can be etched into the thin film windows were shading is required or a decorative façade can be fabricated. Limitation of this application is the light that is allowed into the room.